PCMark04	Source: FutureMark

PCMark04 is an application-based benchmark and a premium tool for measuring overall PC performance. It uses portions of real applications instead of including whole applications or using specifically created code. This allows PCMark04 to maintain a smaller installation size while still giving accurate results.

PCMark04
XP Startup:	MB/s	Ranking
Western Digital Raptor WD740 HDD	11.384
Western Digital Caviar SE16 WD4000KD HDD	9.453
Application Loading:	MB/s	Ranking
Western Digital Raptor WD740 HDD	10.382
Western Digital Caviar SE16 WD4000KD HDD	8.98
File Copying:	MB/s	Ranking
Western Digital Raptor WD740 HDD	50.767
Western Digital Caviar SE16 WD4000KD HDD	51.416
General HDD Usage:	MB/s	Ranking
Western Digital Raptor WD740 HDD	8.882
Western Digital Caviar SE16 WD4000KD HDD	7.916

Here with PCMark04 we see that the Western Digital Caviar SE16 WD4000KD HDD keeps up with the higher RPM Raptor WD740 very well!

PCMark05	Source: FutureMark

PCMark05 is a premium tool for measuring both normal home use and simple 3D performance of the latest PC hardware. There are 11 system tests - each one is designed to represent a certain type of PC usage. By running these tests, PCMark05 stresses the components in a similar manner as they are stressed in normal home usage.

PCMark05:
XP Startup:	MB/s	Ranking
Western Digital Raptor WD740 HDD	11.42
Western Digital Caviar SE16 WD4000KD HDD	9.451
Application Loading:	MB/s	Ranking
Western Digital Raptor WD740 HDD	10.47
Western Digital Caviar SE16 WD4000KD HDD	9.01
General HDD Usage:	MB/s	Ranking
Western Digital Raptor WD740 HDD	8.885
Western Digital Caviar SE16 WD4000KD HDD	7.887
Virus Scan:	MB/s	Ranking
Western Digital Raptor WD740 HDD	89.359
Western Digital Caviar SE16 WD4000KD HDD	91.702
File Write:	MB/s	Ranking
Western Digital Raptor WD740 HDD	70.27
Western Digital Caviar SE16 WD4000KD HDD	62.12

Looks like the 16MB of onboard cache makes a big difference. The Caviar SE16 WD4000KD is even able to outperform the Raptor in the Virus scan portion of PCMark05!